1. Field of the Invention
The present invention relates to a method for producing an electrophotographic photosensitive member.
2. Description of the Related Art
Recently, research and development of electrophotographic photosensitive members (organic electrophotographic photosensitive members) using an organic photoconductive material have been performed actively.
The electrophotographic photosensitive member basically includes a support and a photosensitive layer formed on the support. Actually, however, in order to cover defects of the surface of the support, protect the photosensitive layer from electrical damage, improve charging properties, and improve charge injection prohibiting properties from the support to the photosensitive layer, a variety of layers is often provided between the support and the photosensitive layer.
Among the layers provided between the support and the photosensitive layer, as a layer provided to cover defects of the surface of the support, a layer containing metal oxide particles is known. Usually, the layer containing metal oxide particles has a higher conductivity than that of a layer containing no metal oxide particles (for example, volume resistivity of 1.0×108 to 5.0×1012Ω·cm). Accordingly, even if the film thickness of the layer is increased, residual potential is hardly increased at the time of forming an image. For this reason, the defects of the surface of the support are easily covered. Such a highly conductive layer (hereinafter, referred to as a “conductive layer”) is provided between the support and the photosensitive layer to cover the defects of the surface of the support. Thereby, the tolerable range of the defects of the surface of the support is wider. As a result, the tolerable range of the support to be used is significantly wider, leading to an advantage in that productivity of the electrophotographic photosensitive member can be improved.
Japanese Patent Application Laid-Open No. H06-222600 discloses a technique in which tin oxide particles doped with phosphorus are used for an intermediate layer provided between a support and a photoconductive layer. Japanese Patent Application Laid-Open No. 2003-316059 discloses a technique in which tin oxide particles doped with tungsten are used for a protective layer provided on a photosensitive layer. Japanese Patent Application Laid-Open No. 2007-047736 discloses a technique in which titanium oxide particles coated with oxygen-defective tin oxide are used for a conductive layer provided between a support and a photosensitive layer. Japanese Patent Application Laid-Open No. H06-208238 discloses a technique in which barium sulfate particles coated with tin oxide are used for an intermediate layer provided between a support and a photosensitive layer.
However, examination by the present inventors has revealed that if an image is repeatedly formed under a high temperature and high humidity environment using an electrophotographic photosensitive member employing the layer containing metal oxide particles described above as a conductive layer, then black spots on the output image are likely to be caused by local charge injection from the support to the photosensitive layer.